Rotary pump



Allg 7, 1962 KoJl OHYAGI 3,048,120

ROTARY PUMP Filed Jan. 4, 1961 nited States Patent FatentedAug. 7, 1962 hcc Claims priority, `application Japan Jan. 21, 1960 10 Claims. Cl. 1025-123) This invention relates to a rotary pump for a working v iluid.

Theprimary object of this invention lis to obtain a rotary pump of this type which is simple in construction so that it can be manufactured easily, and in which local abrasion of relatively movable pumping members is comparatively small with the result that temperature rise of the working fluid during operation is also comparatively low.

In order to attain this object, the rotary pump for a working uid according to this invention comprises a cylindrical housing, an approximately cylindrical cage member so arranged in and xed to said housing as to form between it and said housing a discharge passage and provided withplural radial passages, plural pumping follower members inserted movably into said radial passages, a pumping'cam member so arranged in and concontrically to said cage member as to form plural pumping chambers bordering on said cage member and two of said follower members which are kept always in contact with said cam member, and a shaft yfixed to said cam member, said cam member and said shaft having therein Y `suction passages.

Other objects and features of the invention will become more apparent from the following description and accompanying drawing which shows two embodiments of the rotary pump of this invention and in which:

FIG. 1 is a longitudinalsection view of a rotary pump embodying this invention,

FIG. 2 is a cross section view of the same along line II-II in FIG. l, and

FIG. 3 is a schematic end View yof the pumping members and the cage member of another pump embodying this invention. ,p v

Referring to the drawing, particularly to FIGS. 1 and 2, which show a rotary pump with paired pumping cam members displaced angularly from each other by 90, 1 denotes a driving shaft to be driven by a suitable power l source, not shown, such as an electric motor, which shaft is borne .on one hand by an end plate 2 of non-magnetic substance and .on the other hand Iby the end plate part of a cage member 3 of non-magnetic substance fitted fluidtightly in and -iixed to the cylindrical housing 4 of nonmagnetic substance. In the shaft 1 a concentric axial passage 5 is bored to serve as the suction passage of the pump communicating with a central suction opening 6 in the end plate part of the housing 4. The end plate 2 is provided with a cage member 7 projecting inwardly therefrom- The cage members 3 and 7, as Well as a separator disc 8 of non-magnetic material interposed between said members, are so arranged in and -iixed to' the housing 4 as to form an arcuate or annular discharge passage 9 between them and said housing 4. Each of the cage members 3 and 7 having a substantially hollow cylinder prole is provided with four radial passages 10 each for receiving a pumping follower member 11, so that each `cage member 3 or 7 has 4 segmental sections, extending from the end plate part or the end plate 2. Into each of these passages 10, the pumping follower member, eg., a cylindrical roller member -11 of magnetic material as shown is so inserted slidably with its axis parallel to the axis of the shaft 1 as to separate the discharge passage from the pumping chamber 18 or 19. Each of the four segmental sections of the cage member 3 or 7 has therein a discharge valve chamber 12 communicating with the discharge passage 9, into which chamber l12 a ball valve body 13 is inserted together with a compresison spring 14 always pressing the valve ibody 13 toward its seat 15. Onto the shaft 1 paired elliptical pumping cam members 16 and 17 of permanent magnet material, and between which the separator disc 8 is-interposed, are mounted iixedly by an approximately square rlit, as shown, or keyed. The longest radius of ,each of the cam members 16 and y17 is less than the inside radius of each of the cage members 3 and 7, so that the circumferences of the cam members do not touch the inside wall face of either of the cage members. Between these cam members 16, 17 and the cage members 3, 7 there are formed two annular chambers 18, 19 separated by the separator disc 8, each of which chambers is divided into four pumping chambers by the cylindrical roller members 11. Thus, each of the pumping chambers borders on the cam member, two adjacent roller members and the cage member on each side of the separator disc The shaft 1 is provided with two diametrally opposite radial suction passages 20 which communicate at their one ends with the suction passage 5 and at their other ends with radial connecting passages 21 bored in the cam members 16, 17. The housing 4 having the discharge opening 22 is connected with and closed vby the end plate 2, through screws 23 and mounted on the stand 24.

lt is self-evident, as shown in the drawing, that the radial passages l1() are arranged equiangularly, so that all the sections ofthe cage members are exactly of the same proiile and that all the housing, the cagemembers, the cam members and the shaft are arranged coaxially or concentrically to one another.

As shown in FIG. 2, the two radial suction passages 20 are inclined by 45, in a trailing direction, to the maximum diameter of each of the cam members. According to the present invention, the number of lobes of each cam member is 1/2 that of the number of follower members -but is equal to the number of the suction passages. Assuming the number of lobes of each cam member is n, the angle between the maximum radius of the cam member and the adjacent radial suction passage 20, 21 is equal to 360 divided by 4n.

When the shaft 1 is driven in the direction shown by an arrow 25, for example by an electric motor not shown, the pumping cam members 16 and 17 rotate and move to and fro radially the pumping follower members 11 which are kept always iu contact wi-th the members 16 and 17 by magnetic attraction, with the result that on each side of the separator disc S suction of the working fluid is eifected in two diametrally opposite pumping chambers through the connecting passages 21, the suction passages 20, the axial passage 5 and the suction opening 6, while discharge of the uid is effected in the other two diametrally opposite pumping chambers through the ydischarge valve chambers 12, the discharge passage 9 and the discharge opening 22. In the position of the cam member 16 shown in FIG. 2, discharges have been cornpleted in the uppermost and in the lowermost sections of the pumping chamber 18, while in the other two, or lateral, sections, suctions have been completed. Thus the lobes of each of the cam members induce suction and discharge of the working liquid during rotation of the cam members.

If the pumping follower members, i.e., the cylindrical roller members 11 are made of a permanent magnet substance in the embodiment shown in FIGS- 1 and 2, the pumping cam members are made of a paramagnetic Inaterial.

The embodiment shown in FIG. 3 is different from that shown in FIGS. 1 and 2 only in the point that in the former the pumping cam members 16 are of a convex regular triangular form instead of an elliptical form in spaanse the latter, so that numbers of the pumping follower members and the pumping chambers increase correspondingly.

It is here to be noted that in order to form a pumping chamber bordering on each of the cam members, each of the section of the cage members and two follower members, the cam members and the follower members have only to be kept always in line or surface contact, which facilitates construction as well as working of these members and which diminishes eventual local abrasion between these members.

Various changes and modifications may be made without departing from the spirit and scope of this invention. For example, each of the pumping follower members may be a plate or a formed block, instead of a cylinder body. Furthermore, only a single cage member, a single pumping cam member and one set of the pumping follower members may be used in the pump of this invention, in place of the paired cage members, the paired cam members and two sets of the follower members, as shown in FIGS. l and 2.

Having thus described the invention, what is claimed as new and desired to be secured by Letters iatent is:

1. A rotary pump for a working fluid comprising, in combination, a cylindrical housing; substantially cylindrical cage means xed in said housing and dening therewith a substantially arcuate discharge chamber, said cage means being formed with plural first radial passages therethrough equiangularly spaced from each other; plural pumping follower elements each slidably mounted in a respective rst passage for radial reciprocation therein; a rotatable shaft coaxially mounted through said housing and said cage means; a cam xed on said'shaft to rotate therewith and having n lobes equiangularly spaced from each other to` form, with said cage means and pairs of angularly adjacent follower elements, 2n pumping chambers; said cam being formed with n second radial passages each opening into a pumping chamber; said shaft having n radial suction inlets each in radially aligned communication with a respective second passage; the number of first radial passages through said cage means being 2n to form 2n segments of said cage means separated by said rst radial passages, each segment having a discharge passage formed radially therethrough; each second radial passage being angularly displaced from a maximum radius of said cam, in a trailing direction, by an angle equal to 360 divided by 4a; and means maintaining said follower elements continuously engaged with said cam for radial reciprocation thereby.

2. A rotary pump according to claim 1, wherein each of the pumping follower elements is cylindrical.

3. A rotary pump according to claim 1, wherein said cam is of an elliptical profile.

4. A rotary pump according to claim 1, wherein said cam is of a convex regular triangle proiile.

5. A rotary pump for a working uid, as claimed in claim 1, in which said housing and said cage means are formed of non-magnetic material; said follower elements and said cam being formed of paramagnetic material; and said means maintaining said follower elements continuously engaged with said cam comprising magnetic interaction between said follower elements and said cam.

6. A rotary pump for a working fluid, as claimed in claim 1, in which said shaft is hollow for at least part of its length to form an inlet passage for said pump.

7. A rotary pump for a working fluid, as claimed in claim 1, including a spring biased discharge valve in each of said discharge passages.

8. A rotary pump for a working fluid, as claimed in claim 1, in which said cage means comprises a pair of axially adjacent substantially identical cages each formed with said first radial passages and each having follower elements reciprocably mounted in said first radial passages; said cages being relatively angularly displaced; and a separator interposed between said cages; there being a pair of said cams, substantially identical with each other, and each associated with one of said cages, said cams being relatively angularly displaced in accordance with the relative angular displacement of said cages.

9. A rotary pump for a working fluid, as claimed in claim 8, in which said housing and said cages are of diamagnetic material; said cams and said cam followers being of paramagnetic material; and said means maintaining said follower elements continuously engaged with said cams including magnetic coaction between said follower elements and said cams.

10. A rotary pump for a working fluid, as claimed in claim 8, in which said shaft is hollow throughout the length extending through said two cages to form an inlet passage for said pump.

References Cited in the file of this patent UNITED STATES PATENTS 807,421 Dickison Dec. 12, 1905 1,986,202 Hutchison Jan. 1, 1935 2,475,391 Johnson July 5, 1949 2,788,748 Szczepanek Apr. 16, 1957 FOREIGN PATENTS 246,121 Germany Apr. 25, 1912 415,008 Italy Sept. 13, 1946 978,151 France Nov. 22, 1950 

